In an image forming apparatus such as a printer or an MFP (Multi Function Peripheral), with respect to a sheet as a print medium on which an image such as a character is printed, sheets with various characteristics, such as recycle paper, thin sheet, and thick sheet, can be used.
According to the characteristic of a sheet to be used, or the density of a print image, show-through can occur in which a color material penetrated into the print sheet can be visually recognized from the back side of the print sheet. For example, in one-sided printing, the show-through deteriorates the appearance of the back side. Besides, in one-sided printing and two-sided printing, since the color material blurs, the image quality of the print surface is deteriorated. In the two-sided printing, when an image on the print surface overlaps with a show-through image, there is a case where reading becomes difficult.